Recently, IC cards on which a semiconductor IC is mounted have been utilized, instead of magnetic cards widely used e.g. in banks etc. To effect data transmission and its reception between an IC card and a card processing device, a method of electrically connecting the IC card to the card processing device in a contact manner has been usually employed. With this method, the data transmission between the IC provided in the IC card and the card processing device, and the supply of power and a clock signal to the IC are carried out by actually flowing an current through contacts.
However, this contact system requires that contact electrodes are exposed to the card surface, resulting in drawbacks that dusts and the like are attached to the contacts or the contacts are damaged to cause defective or imperfect contact condition, and troubles occur because electrostatic noise is coupled to the contacts, etc. Namely, such spoiled or damaged contacts are unable to securely transmit signals. This prevents the IC card from normally operating, or causes an error in data transfer. Particularly, in the event that a portion or portions between contacts is or are short circuited due to the adhesion of impurities, an erroneous operation of the IC card would occur. Further, when an unexpected high voltage due to electrostatically induced charges etc. is applied, there occurs inconvenience that the IC is the card would be broken, resulting in damage of function of the card itself, loss of data recorded in the card or the like.
For this reason, in stead of such a contact system, some IC cards and processing devices therefor based on non-contact system have been already proposed.
However, any one of non-contact systems is functionally insufficient as compared with the abovementioned contact system.
Namely, one of non-contact systems is limited to the application in which information stored in advance in the IC card is only output to the card processing device, that is, to the application of unidirectional transmission. Another non-contact system is also proposed, which selectively reflects radio wave having a predetermined frequency transmitted from the card processing device in accordance with parameters set to each card. However, with this system, the information rendered by the IC card is of fixed nature, and therefore limited function can be only provided.
An attention is now drawn to a power supply for IC cards. Usually, a solar cell is employed or a contact system is partially used only when a power is supplied. In the former case, viz., when the solar cell is used, the power consumed in the IC card can be obtained, but it is unable to transmit a clock signal required for computer operation to the card processing device and receive it therefrom thus making it impossible to realize highly improved function. On the other hand, in the latter case, although the contact system is employed only in a power supply circuit, occurence of problems due to such contact system cannot be avoided.
Accordingly, it is highly desirable to provide a processing system for IC card, which has the same function as that of the contact system and can eliminate various inconveniences encountered therewith.